Adapter receptacle for a photographic flash gun



y 1961 KENICHI KAWATE 2,984,810

ADAPTER RECEPTACLE FOR A PHOTOGRAPHIC FLASH GUN Filed April 15, 1960 INVENTOR.

KENICHI KAWATE ATTORNEY United States Patent C ADAPTER RECEPTACLE FOR A PHOTOGRAPHIC FLASH GUN Kenichi Kawate, 37 Higashi-ta Katsu Kitano-cho, Tennoji-ku, Osaka, Japan Filed Apr. 15, 1960, Ser. No. 22,437 'Claims priority, application Japan June 15, 1959 3 Claims. (Cl. 339-33) The present invention is concerned with an improved photographic flash bulb socket and particularly with such a socket adapted to receive the small, all-glass, expendable type flash bulbs which are otherwise known in the photographic trade as the AG-l type flash bulb. This particular flash bulb is characterized by a construction which includes an all-glass envelope including a base formed of a substantially flat glass stem. Two electrical terminals for the flash bulb may consist of two electrical conductors which are brought out of the bottom of the glass stem in a generally parallel relationship and are then bent over to lie flat on opposite sides of the flat glass stem so that the two terminals for the flash bulb, which must be energized to ignite the flash bulb, lie on opposite sides of the flat glass stem.

The flash bulb socket of the present invention, which is particularly adapted to receive the above mentioned small all-glass flash bulb, may take the form of an adapter which when used with existing photographic flash guns, adapts these existing flash guns for use with the small all-glass flash bulb.

Specifically, the preferred embodiment of the present invention utilizes an adapter socket or receptacle which includes a body member of electrical insulating material, including a cup-shaped recess or socket opening to receive the glass stern of the small size flash bulb. The socket or receptacle also includes a pair of wide relatively movable metallic contacts which, when moved toward each other, provide an elongated space somewhat smaller than the thickness of the glass stem of the small flash bulb so that when the glass stem is positioned between the metallic contacts, electrical circuit connection is made to the two terminals of the flash bulb and the flash bulb is physically latched to the metallic contacts by the mechanical engagement between the metallic contacts and theterminals of the flash bulb. The adapter socket is provided with a centrally located pin, located in the bottom of the above-mentioned cup-shaped recess. This pin is spring biased and is adapted to be engaged by the base of the flash bulb. The pin is moved against its bias when a flash bulb is positioned in the cup-shaped recess and the pin thereby provides a force to eject a spent flash bulb when the movable metallic contacts are moved apart to release the flash bulb.

As mentioned, this adapter socket or receptacle may be utilized with existing photographic flash guns and particiilarly with flash guns of the type which incorporate a relatively large flash bulb socket adapted to receive the large bayonet base flash bulbs. This large socket is provided with a pair of oppositely disposed axial channels or grooves which receive the bayonet extensions of the bayonet base flash bulb. The adapter socket or receptacle of the present invention may be provided with one or more tabs or ears which mate with the axial channels or grooves of the large socket. By placing these tabs or ears in alignment with the axial channels, the adapter socket may be positioned in the large socket of existing flash guns.

Patented May 16, 1961 The above described existing flash gun is normally provided wtih an eject mechanism, of one type or another, which cooperates with the base of the bayonet base flash bulb to selectively hold or release one of the 5 bayonet extensions thereof to provide selective ejection of spent bayonet base flash bulbs. The adapter socket of the present invention, once it is properly positioned within the large bayonet base socket, has a movable metallic contact positioned in cooperating relation with the eject mechanism of the conventional flash gun so that the posi tion of the metallic contact is controlled by the eject mechanism of the flash gun.

The present invention will be more apparent from the following detailed specification, chaims, and drawings, of which:

Figure 1 is a showing of a portion of a conventional flash gun, in section, and a showing of the adapter receptacle of the present invention mounted in position in the large socket of this flash gun, the adapter receptacle being shown also in section. Furthermore,

Figure 1 shows a side view of the small all-glass type flash bulb in position to be inserted into the socket of the adapter receptacle;

Figure 1a is a top view of the all-glass flash bulb of Figure 1, showing in greater detail the construction of the electrical terminals thereof;

Figure 2 is a section view of the adapter receptacle, similar to the view of Figure 1, wherein the adapter receptacle is removed from the large socket of the conventional flash gun;

Figure 3 is a back view of the adapter receptacle; and

Figure 4 is a front view of the adapter receptacle.

Referring specifically to Figure 1, the reference numera1 10 designates the housing of a conventional flash gun having a large bayonet base socket opening identified generally by means of the reference numeral 11. The large size socket opening of Figure 1 is of the type adapted to receive the relatively large bayonet base flash bulb and the inner diameter of this opening is slightly larger than the diameter of the bayonet base of this type of flash bulb. The bayonet base flash b-ulb has a pair of oppositely disposed bayonet extensions and socket 111 is provided with a pair of channels to receive these extensions, one of the channels coinciding with eject lever 13 so that lever 13 may engage and latch one of the bayonet extensions of the flash bulb.

The reference numeral 12 designates an eject means in the form of a push button which cooperates with the pivoted lever 13, pivoted at 17. The righthand end of lever 13 is biased in a downward direction by means of a leaf spring 14. When the conventional flash gun is utilized with a large bayonet base flash bulb, the righthand end of lever 13 engages one of the bayonet extensions of the bayonet base flash bulb, to both make electrical connection to this portion of the base and to mechanically hold the bayonet base flash bulb. The base of the bayonet base flash bulb includes a centrally located terminal and this terminal is physically engaged for electrical connection by a rod 15. When the eject push button 12 is depressed, the righthand end of lever 13 moves in an upward direction against the bias exerted by spring 14 and the bayonet extension is released so that the bayonet base bulb may be ejected.

The reference numeral 16 designates an annular plate which is fixed on the front of the housing 10.

The adapter receptacle includes a main body member 18 which is constructed of electrical insulating material, for example a form of molded plastic, having a cross section approximating that of the base of a bayonet base flash bulb. The front portion of member 18 includes an annular ring or shoulder 19, which can be seen more clearly in Figures 3 and 4. This member 18 has a hollow recess, identified by reference numeral 20, which is formed in the front center portion thereof and this recess forms a cup-shaped socket opening which is adapted to receive the glass stem or base of the small all-glass flash bulb.

The reference numerals 21 and 22 identify wide metallic contact members which because of their width provide for positive positioning of the flash bulb, as will be apparent. Contact member 21 is mounted in a fixed position at one side of the cup-shaped socket 20 and an extension of this member 21 extends through an opening in shoulder 19 and follows the exterior outline of member 18 to a rear tab, portion which is identified by reference numeral 23. This rear. tab portion, as can be seen in Figure 3, makes electrical connection and is secured in position by means of a metal screw fastener 24 threaded into a boss 56 formed at the back of main body member 18. The adapter socket of Figure 1 is mounted in the relatively large socket opening of the conventional flash Contact 22 is a movable contact and this contact includes a raised button 25 which is adapted to engage the eject means 12'13 of the conventional flash gun. Contact 22 is physically mounted to body member 18 by means of a pair of yoke-like extensions 26 and 27, see Figure 3. The yoke-like extensions extend loosely along opposite sides of the rear portion of body member 18 and contact 22 is biased in an upward direction by means of a spring 28 seated in a recess formed in member 18. The yoke members 26 and 27 are provided with bent over tabs 29 and 30 which limit the upward movement of contact 22.

As can be seen in Figures 2 and 4, when the relatively movable contacts 21 and 22 are moved apart, the space between these terminals is greater than the thickness of the glass stem of the all-glass flash bulb. However, when the adapter receptacle is mounted in position in the conventional type flash gun, as shown in Figure 1, then contact 22 is moved downward to an operative position due to the engagement of member 13 with button 25. The spacing of contacts 21 and 22 is now slightly less than the thickness of the glass stem of the all-glass flash bulb and the socket is adapted to receive and make electrical connection to the terminals of the flash bulb, and to physically hold the flash bulb in position in the socket opening 20.

Referring now to the all-glass flash bulb, reference numeral 40 identifies the glass envelope which includes a substantially flat glass stem 41. The side view of this stem is shown in Figure 1 while the top view is shown in Figure 1a; The electrical terminals of this flash bulb may consist of a pair of wires 42 and 43 which are brought out of the bottom of the glass stem and are bent to lie on opposite sides of the glass stern. This is shown more clearly in Figure 1a wherein the electrical terminal 43 is shown to lie on the top of the glass stem and the electrical terminal 42, shown in broken lines, lies on the bottom of the glass stem.

When the all-glass flash bulb of Figure 1 is inserted into socket opening 20, the terminals 21 and 22 spread slightly, terminal 22 moving against the bias of means 13-14. Electrical connection is completed from the lever 13, through button 25 and contact 22 to terminal 43 of the flash bulb. The electrical connection to the second terminal 42 of the flash bulb is completed through contact 21, screw fastener 24, and rod 15.

The flash bulb 40 is now physically held in position in socket opening 20 by means of engagement between con tact 22 and terminal 43 and the engagement between contact 21' and terminal 42. In actual practice, the flash bulb may be held in position in socket 20 due to the frictional engagement between the contacts and terminals or due to catches or deten'ts which may be formed on the contacts21 and22 to engage the wires 42 and 43.

Reference numeral 50 designates a rod which is centrally positioned within socket 20, as can be seen in" Figure 4. This rod is spring biased to a forward position by means of a spring 51. When flash bulb 40 is inserted into the socket opening 20, rod 50 moves to the left (Figure 1) against the bias of spring 51 and the force exerted against the base of the flash bulb by means of this spring 51 and rod 50 is effective to eject a spent flash bulb from socket opening 20 when the eject button 12 is depressed. 7,

Referring to Figure 1, when this eject button is depressed, member 13 rotates in a counter-clockwise direction about its pivot 17 and allows movable contact 22 to move in an upward direction under the bias of spring 28. As the distance between the contacts 21 and 22 becomes greater, at point is reached where the'base of flash bulb 40 is no longer mechanically held in position and spring 51 is eflective through rod 50 to push the flash bulb out of socket opening 20 to thereby eject the flash bulb.

Referring to Figure 3,'the reference numerals 52 and 53 identify support members which are fixed on opposite sides of body member 18 by means of the screw fasteners 54 and 55. These members 52 and 53 extend along opposite sides of member 18 and cooperate with the yoke members 26 and 27 to loosely hold these members 26 and 27 in position. Furthermore, the upper portions of the members 52 and 53, as shown in Figure 3, have portions which are bent to extend into the vicinity of a boss extension 56 formed in body member 18. a

The members 52 and 53 are also provided with extending bayonet tabs 57 and 58 which lie adjacent an;- nular ring 19 and these tabs are adapted to engage slots formed in the housing 10 of the conventional flash bulb socket to provide mounting of the adapter socket in the position shown in Figure 1.

From the above description it can be seen that Irhave provided an improved flash bulb socket, which maybe an adapter socket as shown in the preferred embodiment, which is simple in construction and is constructed to receive the all-glass type flash bulb.

I claim as my invention:

1. An adapter receptacle for use with a photographic flash gun to facilitate the use of a small size flash bulb having an all-glass envelope with a glass base formed of a flat glass stem having two electrical terminals extending therefrom and positioned on opposite sides of the flat stem, the adapter comprising; a body member of insulating material, said body member having a generally tubu lar shape with an annular shoulder formed at the front face thereof, a cup-shaped socket opening formed in the front face of said body member; a first metallic'contact member fixed to said body member at the rear face there of and extending toward said front face, said first contact member being shaped to conform to the exterior'surface of said body member, an opening in said annular shoulder through which said first contact member extends, and a terminal portion of said first contact member formed to extend into said cupsshaped socket opening to lie at one side of said socket opening; a second metallic contact member including a yoke which loosely embraces opposite sides of said body member to loosely mount said second contact member thereon, a spring mounted between said body member andsaid yoke to bias said second contact member away from said body member to an extent as limited by said yoke, and a terminal portion of said second contact member formed to movably extend through an opening in the side of said body member and into said socket opening to lie at the opposite side of said socket opening; and a push rod movably mountedin the bottom of said cup-shaped socket opening and biased to extend generally between the terminal portions of said first and secondcontact members; said terminal portion of said second contact member, when moved toward the center of'said; socket opening, being adapted to receive and hold the base of thei'small size flash bulb} with said push rod then exerting a force on th'e base of the bulb, which force is effective to eject a spent bulb from the socket opening when the terminal portion of said second contact member is subsequently moved away from the center of said socket opening.

2. An adapter flash bulb socket for use with a photographic flash gun of the type having a bayonet base socket with oppositely disposed channels to receive the bayonet extensions of a bayonet base flash bulb; having a movable metallic eject lever to latch and make electrical connection to one terminal of this flash bulb, the lever being mounted at one of the channels to latch one of the bayonet extensions of this flash bulb, and the eject lever being selectively movable to unlatch this bayonet extension; and having a contact centrally located in the bayonet base socket to make electrical connection to the other terminal of the flash bulb; the adapter flash bulb socket facilitating the use of a small all-glass flash bulb having a base formed of a flat glass stem with electrical terminals disposed on opposite sides of the glass stem, the adapter flash bulb socket comprising; a tubular shaped insulating body member having a cross section substantially equal to that of the base of a bayonet base flash bulb, a small flash bulb socket formed in a front face of said body member; a first contact member mounted in a fixed position at one side of said small flash bulb socket and having a first portion thereof extending a distance into said small flash bulb socket and a second portion extending to the rear face of said body member to make electrical connection to the centrally located contact of the bayonet base socket; a second contact member movably mounted at the opposite side of said small flash bulb socket having a first portion thereof extending a distance into said small bulb socket and a second portion extending along one side of said body member to engage and make electrical connection to the eject lever of the bayonet base socket; and a movable push rod mounted at the bottom of said small flash bulb socket and biased to extend generally between said portions of said contact members; the adapter flash bulb socket being adapted to be positioned within the bayonet base socket with said contact members in alignment with the oppositely disposed channels thereof and with the second portion of said second contact member being engaged and held in an operative position by the movable eject lever such that said second contact member is moved toward said first contact member and the resultant distance between said first portions of said contact member is somewhat less than the thickness of the glass stem of the small flash bulb.

3. In combination, a large photographic flash bulb socket for use with the large bayonet base flash bulb having a pair of oppositely disposed bayonet extensions, a pair of oppositely disposed channels formed in said large socket adapted to receive the bayonet extensions of the bayonet base flash bulb, a spring biased eject lever extending into one of said channels and biased to engage and mechanically hold one of the bayonet extensions of a bayonet base flash bulb which may be inserted in said large socket, an insulating body member of a size substantially equal to the base of the bayonet base flash bulb, an open cup-shaped recess formed in the front face of said body member, a fixed contact mounted at one side of said recess having a portion which extends into said recess, a movable contact mounted at the opposite side of said recess and also having a portion which extends into said recess, a movable push rod mounted at the bottom of said cup-shaped recess and biased to extend generally between said portions of said contacts, a pair of radially extending oppositely disposed bayonet tabs mounted on said body member so that said body member may be inserted into said large socket with said tabs in alignment with the channels thereof and said body member may thereby be mounted in said large socket, said movable contact when being moved into engagement with said eject lever such that said movable contact is then moved toward said fixed contact, the resultant spacing of said contacts being somewhat less than the thickness of the base of a small all-glass flash bulb of the type having a flat glass base with terminals located on opposite sides of the glass base.

References Cited in the file of this patent UNITED STATES PATENTS 963,733 Kliegl July 5, 1910 2,565,492 French Aug. 28, 1951 2,691,143 Lawson Oct. 5, 1954 

